1. Field of the Invention
The present invention relates to a thin loudspeaker having a relatively low profile.
2. Description of the Related Art
A loudspeaker structure is disclosed in Japanese Laid-Open Patent Publication No. 55-64500, which includes a yoke having slits formed therein, and support members inserted in the slits, such that a voice coil and a diaphragm are coupled via the support members.
FIG. 39 is a cross-sectional view illustrating a conventional loudspeaker 7000 disclosed in Japanese Laid-Open Patent Publication No. 55-64500. FIG. 40 is a plan view illustrating a magnetic circuit and associated elements, as viewed from above a diaphragm 8 of the loudspeaker 7000.
The loudspeaker 7000 includes: a bottom plate 23; a magnet 1 provided on the bottom plate 23; a center pole 2 provided on the magnetic 1; a yoke 3 which is provided so as to surround the center pole 2 and which has a plurality of slits 11 in a radial arrangement; a coupling member 37; a voice coil 39 affixed to the inner periphery of the coupling member 37; a diaphragm 8 and dampers 10 affixed to the outer periphery of the coupling member 37; frames 12A and 12B; and a cover 34. The coupling member 37 has support members 35 to be inserted in the plurality of slits 11, and inner and outer rings 36 and 46.
The magnet 1, the center pole 2, the yoke 3, and the bottom plate 23 together compose a magnetic circuit. A magnetic flux is generated within a magnetic gap 4 by the magnetic circuit.
As an electric input is supplied to the voice coil 39 in the above structure, a driving force along a vertical direction is generated in the voice coil 39 according to Fleming""s left-hand rule, due to the magnetic flux generated within the magnetic gap 4. Since the diaphragm 8 is coupled to the voice coil 39 by means of the coupling member 37 (i.e., via the support members 35), the driving force generated in the voice coil 39 is transmitted to the diaphragm 8, which vibrates and emits sound. Since this structure prevents the diaphragm 8 from contacting an upper face 3A of the yoke 3, there is no need to allow for an amplitude margin when designing the total height of the loudspeaker 7000. As a result, the total height h can be reduced.
FIG. 41 is a plan view showing a cylindrical coupling member 47 disclosed in Japanese Laid-Open Patent Publication No. 55-64500, supra. The cylindrical coupling member 47 is composed of an elongated metal foil which is folded at periodic lengths, so that the folded portions are linked together to form protruding support members 45 of the cylindrical coupling member 47. A voice coil 39 is affixed to the inner periphery of the coupling member 47.
However, in accordance with the loudspeaker 7000 shown in FIGS. 39 and 40, it is necessary to attach the coupling member 37 to the outer periphery of the voice coil 39. As the wire diameter for the voice coil 39 is changed in order to obtain various levels of driving force, the outer diameter of the voice coil 39 also varies. This necessitates a change in the inner diameter of the inner periphery of the coupling member 37 to which the voice coil 39 is attached. In other words, for each voice coil 39, a coupling member 37 having corresponding geometry must be designed. This presents a problem, when mass producing various models, in that costs associated with the production of component parts and the production facility itself are increased, and that the storage and management of varying component parts becomes cumbersome.
On the other hand, in the case where the coupling member 47 with support members 45 as shown in FIG. 41 is formed by folding a thin metal foil (especially due to mass productivity-related concerns), the support members 45 can only be adhered to the diaphragm 8 and the dampers 10 in an extremely small adhesion area, resulting in a poor adhesion strength. Consequently, peeling associated with the diaphragm 8 moving with a large amplitude or failure of the driving force generated in the voice coil 39 to be transmitted to the diaphragm 8 may occur, thereby unfavorably affecting the sound pressure characteristics of the loudspeaker 7000.
According to the present invention, there is provided a loudspeaker including: a bottom plate; a center pole provided upwardly from the bottom plate; a yoke surrounding the center pole and having a plurality of slits; a magnet for providing a magnetic flux for the center pole and the yoke; a coil provided between the center pole and the yoke; a first annular member for supporting the coil; a plurality of support members for supporting the first annular member, the plurality of support members being inserted into the plurality of slits; and a diaphragm supported by the plurality of support members, wherein upper faces of the plurality of support members gradually decrease in height in a direction away from the first annular member, and wherein a lower face of the coil is located below a position at which the diaphragm is supported by the plurality of support members.
In one embodiment of the invention, the lower face of the coil is located below lower faces of the plurality of support members.
In another embodiment of the invention, the coil is provided at an outer periphery of the first annular member.
In still another embodiment of the invention, the loudspeaker further includes a plurality of dampers for supporting the plurality of support members.
In still another embodiment of the invention, the plurality of support members each have a plate-like shape.
In still another embodiment of the invention, the loudspeaker further includes a second annular member provided between the plurality of support members and the first annular member, wherein the plurality of support members support the first annular member via the second annular member.
In still another embodiment of the invention, the plurality of support members and the first annular member are formed as an integral piece.
In still another embodiment of the invention, the plurality of support members and the second annular member are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a third annular member provided between the plurality of support members and the diaphragm, wherein the plurality of support members support the diaphragm via the third annular member.
In still another embodiment of the invention, the loudspeaker further includes a third annular member provided between the plurality of support members and the plurality of dampers, wherein the plurality of dampers support the plurality of support members via the third annular member.
In still another embodiment of the invention, the plurality of support members and the third annular member are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a second annular member provided between the plurality of support members and the first annular member, wherein the plurality of support members support the first annular member via the second annular member.
In still another embodiment of the invention, the magnet is provided between the bottom plate and the center pole.
In still another embodiment of the invention, the bottom plate and the yoke are formed as an integral piece.
In still another embodiment of the invention, the magnet surrounds the center pole.
In still another embodiment of the invention, the magnet has a plurality of slits; and the plurality of slits of the magnet are disposed so as to be aligned with the plurality of slits of the yoke.
In still another embodiment of the invention, the bottom plate and the center pole are formed as an integral piece.
In still another embodiment of the invention, the first annular member is supported at a first end of each of the plurality of support members, and the diaphragm is supported at a second end of each of the plurality of support members; and a lower face of each of the plurality of support members has a stepped configuration such that the lower face is lower at the second end than at the first end.
In still another embodiment of the invention, the loudspeaker further includes a cover provided so as to cover an upper face of the center pole.
In still another embodiment of the invention, the cover and the first annular member are formed as an integral piece.
Alternatively, a loudspeaker according to the present invention includes: a bottom plate; a center pole provided upwardly from the bottom plate; a yoke surrounding the center pole and having a plurality of slits; a magnet for providing a magnetic flux for the center pole and the yoke; a coil provided between the center pole and the yoke; a first annular member for supporting the coil; a coupling member composed essentially of a plate material folded into an annular shape having a plurality of protruding portions, the coupling member supporting the first annular member, wherein one of the plurality of protruding portions is inserted into two of the plurality of slits; and a diaphragm supported by the coupling member.
In one embodiment of the invention, the loudspeaker further includes a plurality of dampers for supporting the coupling member.
In another embodiment of the invention, the loudspeaker further includes a cover provided so as to cover an upper face of the center pole.
In still another embodiment of the invention, the cover and the first annular member are formed as an integral piece.
Alternatively, a loudspeaker according to the present invention includes: a bottom plate; a center pole provided upwardly from the bottom plate; a yoke surrounding the center pole and having a plurality of slits; a magnet for providing a magnetic flux for the center pole and the yoke; a coil provided between the center pole and the yoke; a coupling member composed essentially of a plate material folded into an annular shape having a plurality of protruding portions, the coupling member supporting the coil, wherein one of the plurality of protruding portions is inserted into two of the plurality of slits; and a diaphragm supported by the coupling member.
In still another embodiment of the invention, the loudspeaker further includes a plurality of dampers for supporting the coupling member.
Alternatively, a loudspeaker according to the present invention includes: a bottom plate; a center pole provided upwardly from the bottom plate; a yoke surrounding the center pole and having a plurality of slits; a magnet for providing a magnetic flux for the center pole and the yoke; a coil provided between the center pole and the yoke; a first annular member for supporting the coil; a plurality of support members, each having a first end and a second end, for supporting the first annular member at the first ends, the plurality of support members being inserted into the plurality of slits; and a diaphragm supported by the plurality of support members at the second ends, wherein a lower face of each of the plurality of support members has a stepped configuration such that the lower face is lower at the second end than at the first end, and the diaphragm supported by the plurality of support members at the second ends is supported at a position below the lower face, at the first end, of each of the plurality of support members.
In one embodiment of the invention, the coil is provided at an outer periphery of the first annular member.
In another embodiment of the invention, the loudspeaker further includes a plurality of dampers for supporting the plurality of support members.
In still another embodiment of the invention, the loudspeaker further includes a second annular member provided between the plurality of support members and the first annular member, wherein the plurality of support members support the first annular member via the second annular member.
In still another embodiment of the invention, the plurality of support members and the first annular member are formed as an integral piece.
In still another embodiment of the invention, the plurality of support members and the second annular member are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a third annular member provided between the plurality of support members and the diaphragm, wherein the plurality of support members support the diaphragm via the third annular member.
In still another embodiment of the invention, the loudspeaker further includes a third annular member provided between the plurality of support members and the plurality of dampers, wherein the plurality of dampers support the plurality of support members via the third annular member.
In still another embodiment of the invention, the plurality of support members and the third annular member are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a second annular member provided between the plurality of support members and the first annular member, wherein the plurality of support members are interposed between the second annular member and the third annular member.
In still another embodiment of the invention, the magnet is provided between the bottom plate and the center pole.
In still another embodiment of the invention, the bottom plate and the yoke are formed as an integral piece.
In still another embodiment of the invention, the magnet surrounds the center pole.
In still another embodiment of the invention, the magnet has a plurality of slits; and the plurality of slits of the magnet are disposed so as to be aligned with the plurality of slits of the yoke.
In still another embodiment of the invention, the bottom plate and the center pole are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a thin plate for interconnecting upper faces of at least two of the plurality of support members.
In still another embodiment of the invention, the second end of each of the plurality of support members has a height-wise dimension greater than a height-wise dimension of the first end of the support member.
In still another embodiment of the invention, the loudspeaker further includes a cover provided so as to cover an upper face of the center pole.
In still another embodiment of the invention, the cover and the first annular member are formed as an integral piece.
Alternatively, a loudspeaker according to the present invention includes: a bottom plate; a center pole provided upwardly from the bottom plate; a yoke surrounding the center pole and having a plurality of slits; a magnet for providing a magnetic flux for the center pole and the yoke; a coil provided between the center pole and the yoke; a first annular member for supporting the coil; a plurality of support members for supporting the first annular member, the plurality of support members being inserted into the plurality of slits; a diaphragm supported by the plurality of support members; and a second annular member provided between the plurality of support members and the diaphragm, wherein the plurality of support members support the diaphragm via the second annular member, and wherein a plurality of thin plates for reinforcing the second annular member are provided at at least one of an inner periphery and an outer periphery of the second annular member.
In one embodiment of the invention, each of the plurality of support members has a constant dimension in a direction of vibration of the diaphragm.
In another embodiment of the invention, the second annular member and the plurality of thin plates are formed as an integral piece.
In still another embodiment of the invention, the loudspeaker further includes a third annular member provided between the plurality of support members and the first annular member, wherein the plurality of support members are interposed between the second annular member and the third annular member.
In still another embodiment of the invention, the loudspeaker further includes a thin plate for interconnecting upper faces of at least two of the plurality of support members.
In still another embodiment of the invention, the first annular member is supported at a first end of each of the plurality of support members, and the diaphragm is supported at a second end of each of the plurality of support members; and a lower face of each of the plurality of support members has a stepped configuration such that the lower face is lower at the second end than at the first end.
In still another embodiment of the invention, the second end of each of the plurality of support members has a height-wise dimension greater than a height-wise dimension of the first end of the support member.
In still another embodiment of the invention, the plurality of thin plates are provided at an outer periphery of the second annular member; the number of thin plates is equal to the number of support members; and the plurality of thin plates are positioned on extensions of the plurality of support members along a radial direction of the first annular member.
In still another embodiment of the invention, the plurality of thin plates are provided at an inner periphery of the second annular member; and at least one of the plurality of thin plates is provided in closer proximity to one of the plurality of support members than to others of the plurality of thin plates.
In still another embodiment of the invention, a lower face of the coil is located below lower faces of the plurality of support members.
In still another embodiment of the invention, the coil is provided at an outer periphery of the first annular member.
In still another embodiment of the invention, the loudspeaker further includes a cover provided so as to cover an upper face of the center pole.
In still another embodiment of the invention, the cover and the first annular member are formed as an integral piece.
Thus, the invention described herein makes possible the advantage of providing a loudspeaker incorporating a coupling member having a small mass and high mechanical strength, which can reduce the production cost associated with the mass production of various models and which can provide a sufficient vibration amplitude.
This and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.